staging: rtl8188eu: Remove function rtw_modular64()

Remove function rtw_modular64 as all it does is call do_div.
Replace call to rtw_modular64 with call to do_div.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lore.kernel.org/r/20190712071746.2474-5-nishkadg.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>